In a sewing machine stitch, a stitching method called “free motion stitch” is known. In this free motion stitch, a cloth feeding motion of the sewing machine is disabled, and the cloth feeding is not performed, and an operator moves the cloth freely to achieve the sewing machine stitch. In the sewing machine provided with a zigzag motion mechanism for zigzag stitch, a wide variety of free motion stitches is achieved by adding the zigzag stitch.
In the free motion stitch, since the operator moves the cloth with both hands, speed of the sewing machine is adjusted by a foot controller.
Adjustment of the extent of the zigzag width (zigzag needle motion width) that is, an amplitude value is normally performed with an operating device referred to as “knee lifter” that can be operated by a knee. By the operation of the knee lifter, the width of zigzag stitch is adjusted.